Weakness is a reduction in the strength of one or more muscles.
Alternative Names
Lack of strength; Muscle weakness
Considerations
Weakness may be generalized (total body weakness) or localized to only one area, side of the body, limb, or muscle. Weakness is more notable when it is localized. Localized weakness may follow a
Weakness may be subjective or objective.
- Subjective means you feel weak, but there is no measurable loss of strength. For example, you may feel weak if you have infectious diseases such as
mononucleosis andthe flu . - Objective means there is a measurable loss of strength noted during a physical exam.
Common Causes
Measurable weakness may result from a variety of conditions including metabolic, neurologic, primary muscular diseases, and toxic disorders.
METABOLIC
-
Addison's disease - Hyperparathyroidism
- Low sodium or potassium
-
Thyrotoxicosis
NEUROLOGIC
-
Amyotrophic lateral sclerosis - Bell's palsy
-
Cerebral palsy -
Guillain-Barre syndrome - Multiple sclerosis
- Pinched nerve (for example, caused by a slipped disk in the spine)
- Stroke
PRIMARY MUSCULAR DISEASES
- Becker muscular dystrophy
-
Dermatomyositis -
Muscular dystrophy (Duchenne) - Myotonic dystrophy
TOXIC
-
Botulism - Organophosphate poisoning (
insecticides , nerve gas) - Paralytic
shellfish poisoning
OTHER
- Anemia
-
Myasthenia gravis -
Poliomyelitis












